On the outright it seems disrespectful to the deceased. The only things I can think of are:
-To place the remains in a more public friendly space such as a church so that the local graveyard does not get overwhelmed by visitors.
-To protect the remains from relic hunters.
Is the examination of the actual remains of the candidate a requirement in the canonization process?
Actually, it is part of the required process for beatification. The process is an involved one that occurs in many facets. One facet is for there to be a
recognitio of the remains and their condition. It can happen that the remains are found incorrupt. It can also happen that the remains have completely decomposed…or any state in between. This information is part of the dossier of the Congregation for the Causes of Saints, the Vatican dicastery that deals with this.
This is a moment for elements of the remains to be extracted for eventual
ex corpore relics, after beatification. These are entrusted to the postulator and to the Vicariato of Rome, respectively. These relics will, for example, be used in altars that are designed to enclose the relic of a saint/blessed.
You are correct that the remains, after exhumation, are many times translated to a place that favours visits/pilgrimages. The traditional presentation of these was in a recumbent figure that artistically depicted the saint or blessed. This custom is becoming less common in more recent years, instead having a casket or other solid repository holding the remains in a manner that does not make them in any way visible.
Removal/relocation is not always the case. The remains of Saint Gianna Molla, for example, are in a grave in the cemetery; they were not moved at the time of her beatification or subsequently.
Some times, it is not possible to identify any remains of the deceased. The body of the North American martyr, Rene Goupil, was lost at the time of his martyrdom and has never been recovered though the general vicinity of where it should be is known. Martyrs killed under Nazi Germany were normally cremated after being killed or else otherwise buried in mass graves. No identifications could be done, for example, of the remains of Saint Edith Stein or Saint Maximilian Kolbe.
